1. Field of the Invention
This invention relates generally to heat pumps. In particular, this invention relates to an advanced heat pump which uses a liquid desiccant to remove moisture from outside air and then transfer the moisture to dry heated air inside of a building.
2. Description of the Prior Art and Objectives of the Invention
Engineers have known for many years that the evaporator and condenser in refrigeration equipment can be interchanged by reversing the direction of the refrigerant flow from the compressor. By reversing the flow direction either a heating or cooling function can be performed and such refrigeration equipment which is commonly referred to as a heat pump generally includes an outdoor coil which is positioned on the exterior of the building, an indoor coil positioned within the building and an expansion valve for reducing the pressure of the refrigerant. Both the indoor and outdoor coil function as a condenser or as an evaporator depending on whether the heat pump is operating in a cooling cycle or a heating cycle.
Various types of heat pumps having reverse refrigeration cycles which may be either self contained or split (condenser and evaporator in separate locations) have met with moderate success in certain installations, but have also had certain disadvantages. For example, conventional heat pumps use freon or refrigerants with relative high boiling temperatures (boiling point between 0.degree. F. and 32.degree. F.) to inhibit frost formation on evaporator surfaces when the outside air temperature falls below 40.degree. F. In addition, these heat pumps generally require another heat source such as electric heating coils to melt frost accumulations on evaporators. This generally limits the use of conventional heat pumps to geographic regions having mild winters such as Virginia, Maryland and North Carolina. Further, conventional heat pump systems dehumidify the air during the heating mode of operative often requiring the installation of complex and expensive auxiliary equipment to maintain a suitable interior building humidity.
With these and other disadvantages known to conventional heat pump systems, the present invention was conceived and one of its objectives is to provide a heat pump which is economical to use and provides satisfactory results and low maintenance and operating cost for the user.
It is another object of the present invention to provide a heat pump which removes water vapor from outside air and thereby prevents frost formation on a cold evaporator.
It is still another object of the present invention to utilize the condensation collected from the outside air to humidify air inside of a building during the heating cycle.
It is yet another object of the present invention to provide a heat pump which uses low temperature boiling point refrigerants to improve operating efficiency and provide for operability in cold weather geographic locations.
Various other advantages and objectives will become apparent to those skilled in the art as a more detailed description of the invention is set forth below.